What was supposed to be a night of epic rock music at Morrison, CO’s Red Rocks Amphitheatre on June 10th, 1971 turned into an all-out riot when Jethro Tull came to town. The infamous night nearly became the last-ever rock show ever held at the famous outdoor venue.

The hot summer evening 52 years ago tonight brought 10,000 die-hard fans from around the country to see the famous British rock band’s performance, which sold out nearly two weeks ahead of the show. An hour before showtime, however, nearly 2,000 ticketless fans outside the venue caused a commotion when they attempted to climb the hills behind the venue in order to sneak in. As the situation snowballed and fans followed the example of the gate-crashers around them, police onsite responded with copious amounts of tear gas in an attempt to disperse the crowd.

The fracas that followed would go down as one of the worst riots in rock history, and nearly got rock concerts banned from the venue for good. After being provoked, fans unable to get in began throwing rocks and bottles at police, tipping cars, and generally initiating chaos around the venue. Due to the shape of the natural amphitheater, the venue filled with tear gas from outside the gates at an alarming rate, forcing the night’s opening act, Livingston Taylor, to make a quick exit before finishing his set.

Related: Phish Kicked Off An Infamous Red Rocks Run, On This Day In 1996 [Video/Full-Show Audio]

As the riots continued, fans already settled in their seats began experiencing the effects of the chaos. Hundreds sustained injuries ranging from broken bones to cuts from broken glass, while some even passed out due to the sudden influx of tear gas. Tull’s manager, Terry Ellis, arrived at the peak of the riots and was quickly turned away in his car by police who stated, “The concert’s over. Turn around and get out.” After explaining who they were, the band managed to get backstage, but they quickly realized the grim reality of what the concert had become.

The band turned around upon witnessing the chaos but had parked on the side of the road to further investigate. Helicopters started flying low and dropping more tear gas over the venue as the crowd ran for the exits. After a few minutes passed, the members of Jethro Tull proceeded back up the one-mile road into the park and entered a backstage area littered with broken glass, fumes of tear gas, unconscious fans, and unlucky attendees with blood running down their faces and clothes. Apparently, venue organizers and city officials had battled for two years leading up to the show to allow Red Rocks to host rock concerts, and Jethro Tull was supposed to be the first band to kick it off.

Promoter Barry Fey said, “Well, I guess, what happened here, I don’t know how many gate crashers—six hundred to a thousand is what they estimate—were over the top there. And I guess it got out of hand. I guess they took a couple of police away to the hospital. And someone threw tear gas, and it drifted over. And of course, the innocent people get hurt It seems to be settled down now, but it’s hard to control up here. There’s no communications, you can see it’s so vast that you don’t really know what’s going on.”

Amid the chaos, Jethro Tull’s Ian Anderson went on stage with his guitar, and the crowd cheered knowing that music would prevail. After the first song, Anderson said to the crowd, “Welcome to World War Three.”

Throughout the show, more canisters of tear gas continued to explode in the crowd, resulting in the band also inhaling the fumes as they played on. The music continued for nearly an hour and a half as the band played through its then-new album, Aqualung, soothing the crowd with some more spiritual tunes. In the end, 28 people, including Denver policemen and three infants, were treated at hospitals for injuries sustained during the riot while hundreds were treated onsite by medical teams. A few dozen fans were arrested.

In the aftermath of the riot, Sam Feiner, director of Denver’s Theaters-Arenas Division, said he wouldn’t allow any more rock events at Red Rocks as a result of the disturbances. The restriction lasted through 1976.

The only other act that has been banned by Morrison city officials in the years since the Jethro Tull catastrophe is Phish who were temporarily barred from Red Rocks after riots broke out during a 1996 performance. They did not return until 2009.

Watch Ian Anderson discuss the 1971 riots during Jethro Tull’s return to Red Rocks in 2008 via the fan shot below.

Ian Anderson Talks 1971 Riots During 2008 Red Rocks Amphitheater Performance

[Video: Grateful Web]